gcc/testsuite/g++.dg/cpp2a/concepts-requires13.C

// { dg-do compile { target c++20 } }

template <class T> concept C = true;

template <class T>
  requires C<typename T::foo>
void f(T t) { }

void f(...);

template <class T>
  requires C<T>
void g(T t) { }

int main()
{
  f(42);
  g(42);
}